We report on a microscopic investigation of the polariton parametric emission in the presence of coherent and incoherent interaction processes by means of a full quantum description based on a nonequilibrium quantum Langevin approach for open systems applied to interacting-electron complexes described within the dynamics controlled truncation scheme. It provides an easy recipe to calculate multi-time correlation functions which are key-quantities in quantum optics. In particular we report on calculations of polariton intensities (i.e. single time correlators) and spectra (i.e. two times correlators). We apply our scheme to a two-pumps set-up in microcavity recently proposed showing a quantitative analysis of the quantum correlation properties of the emitted photons. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.